were gassed at Sonnenstein Castle and Bernburg. From March to April 1942, some 1,600 women were selected at Ravensbrück and gassed at Bernburg. The "medical reviews" are described in an excerpt from letters written by Dr. Friedrich Mennecke; during a selection at Buchenwald, Mennecke wrote to his wife; Killing centers Only three Nazi killing centers (NS-Tötungsanstalt) were used for the gassing of the invalided prisoners: Bernburg Killing Facility (manager: Irmfried Eberl), Sonnenstein Killing Facility (manager: Horst Schumann), and Hartheim Killing Facility (Rudolf Lonauer and Georg Renno). Under the code name "Aktion 14f13" prisoners from Mauthausen and Gusen were murdered at Hartheim Castle starting in July 1941. After the doctors' commissions had invalided the concentration camps' prisoners, the camp administration had to provide them on request. They were transported either by the "Gekrat" or the Reichsbahn to one of the killing centers. The prisoners were examined for gold teeth by a prison doctor and labelled appropriately before being led into a gas chamber, where they were murdered with carbon monoxide. After any gold teeth were removed, for dispatch to a central office in Berlin, the corpses were incinerated in the crematorium; some corpses were examined further before incineration. The murder was carried out by the same staff, using the same means as used previously with the mentally ill in Aktion T4. A few administrative details were changed, in that the murders were recorded by members of the respective camp administration; they informed relatives of the deaths, claiming illness as the cause. A detailed description was given by Vincent Nohe to the Linz Kriminalpolizei in September 1945, who were investigating Nazi war crimes that had taken place nearby. Nohe, who had worked as a "burner" in the crematorium at the Hartheim Killing Facility, was convicted at the Dachau-Mauthausen Trial in 1946 and sentenced to death, for the murder of sick and incapacitated concentration camp prisoners and was executed in 1947. Scope of selections Selections increasingly included political or other persecuted peoples, Jews and so-called asoziale. Pursuant to the general guidelines of the Bavarian police of August 1, 1936, those to be taken into Schutzhaft ("protective custody") were "gypsies, vagrants, tramps, the "work-shy", idlers, beggars, prostitutes, troublemakers, career criminals, rowdies, traffic violators, psychopaths and the mentally ill." Shortages of labour for the war economy led to a Concentration Camps Inspectorate (CCI) decree on March 26, 1942, which was distributed to all camp commandants.